TomTom made some mistakes when filtering the list of owners' devices when sending this email.
What makes it more confusing is that the numbering for the code branches between models is so similar.
It turns out that the 25.100.0001 version reference in the email applies to the generation just prior to the Rider 550 model, and includes the following and NOT models that came later:
GO 40, GO 50, GO 51, GO 60, GO 61, GO 400, GO 500, GO 510, GO 600, GO 610, GO 5000, GO 5100, GO 6000, GO 6100, START 40, START 50, START 60, START 42, START 52, START 62, VIA 52, VIA 62, RIDER 40/400/410/42/420/450, Trucker 500/5000/6000